This invention relates to microwave multiplexers operative with plural channels of electromagnetic signals and, more particularly, to the multiplexing signals of differing frequencies of a first set of signal channels with signals of differing frequencies of a second set of signal channels, wherein the first channel signals are circularly polarized and the second channel signals are linearly polarized prior to a combining of the two sets of signals.
Microwave multiplexers are employed in communication systems, such as in satellite communication systems, for combining numerous signal channels for transmission along a common transmission path such as an antenna feed. In a frequently employed form of satellite communication system, an antenna carried by a satellite transmits and/or receives electromagnetic signals propagating between the satellite and an antenna located on the earth's surface. Plural signal channels separated by frequency and/or by polarization are communicated by the two antennas. It is important that the signals of all the channels, whether they be linearly polarized or circularly polarized, propagate along the same path in a common direction so that all of the signals transmitted by a transmit antenna reach a receive antenna.
While multiplexing systems have been employed in both land-based and in satellite communication systems, a problem arises in that they have entailed mechanical complexity with undesirably heavy structures At present, multiplexing systems with adequate mechanical simplicity and reduced mass, suitable for use in satellite and ground-based communication systems are unavailable.